In electric hammers, a motor is accommodated in a rear housing, and a striking mechanism having a piston that reciprocates within a cylinder and a striking element that operates together with the piston via an air chamber is accommodated in a rear part of a cylindrical barrel coupled in front of the rear housing. A tool holder including at its front end a mount portion for a bit is shaft-supported in a front part of the barrel. Thus, when the piston reciprocates by driving of the motor, the striking element reciprocates together with the piston due to the action of an air spring, thereby striking the bit mounted to the tool holder, either directly or indirectly via an intermediate element (see, e.g., Patent Document 1).
Such electric hammers are sometimes provided with an angle adjustment mechanism capable of arbitrarily adjusting an angle about the axis of the bit. In this angle adjustment mechanism, the tool holder is rotatably provided, a change ring is mounted on the outer periphery of the tool holder so as to be rotatable together with the tool holder, and to be slidable in an axial direction, and a lock ring having a cam face that engages with the change ring is non-rotatably mounted behind the change ring on the tool holder. In a normal state, the change ring is moved rearward by biasing means such as a coil spring to a position where the change ring engages with the lock ring, whereby the angle of the tool holder and the bit is fixed. On the other hand, when the change ring is moved forward against the biasing means to disengage the change ring from the lock ring, the tool holder and the bit are allowed to rotate to any angle by rotation of the change ring.